Bicomponent or multicomponent fibers and methods of making the same

ABSTRACT

Disclosed herein are systems, devices, and method for forming bicomponent or multicomponent nanofibers.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. § 119(e) of the U.S.Provisional Application Ser. No. 62/596,057 filed Dec. 7, 2017, thecontent of which is hereby incorporated by reference in its entirety.

BACKGROUND

Fibrous media, e.g., comprising polymer fibers, are used in a variety ofdiverse applications, such as medical and protective garments,insulation, filters, ceiling tiles, battery separator media, tissueengineering scaffolds, etc. There is a need in the art, however, forcustomizable and uniquely arranged bicomponent or multicomponent fibersthat provide particular structural and/or functional benefits.

SUMMARY

The present disclosure provides unique bicomponent or multicomponentfibers, and customizable systems, devices, and methods for fabricationof the same.

Accordingly, in one embodiment, provided herein is a first method ofpreparing a bicomponent or multicomponent nanofiber with anelectrospinning device that comprises a spinneret comprising a firstchannel and a second channel inside the first channel. The method, insome embodiments comprises: supplying a solution of a first polymer to afirst channel; supplying a solution of a second polymer to the secondchannel; and electrospinning the solutions, through the respectivechannels, onto the surface of a substrate; thereby preparing a fibrousstructure comprising fibers having a first layer and a second layerinside the first layer, wherein the first layer comprises the firstpolymer and the second layer comprises the second polymer.

In some embodiments of the first method, the first and second polymersdisclosed herein have different dipole moments. In some embodiments, thefirst polymer has a dipole moment greater than about 2 D (Debye) and thesecond polymer has a dipole moment lower than about 1 D.

In some embodiments of the first method, the first channel and secondchannel of the spinneret are coaxial.

In some embodiments of the first method, said method further comprisessupplying a solution of a third polymer to a third channel of thespinneret, wherein the third channel is inside the second channel,thereby resulting in prepared fibers comprising a first layer, a secondlayer inside the first layer, and a third layer inside the second layer.The first, second, and third layers may comprise the first, second andthird polymers, respectively. In some embodiments, the third polymer hasa dipole moment greater than the dipole moment of the second polymer. Insome embodiments, the third polymer has a dipole moment greater than thesecond polymer, and less than the dipole moment of the first polymer. Insome embodiment, the third polymer has a dipole moment greater than thedipole moment of the second polymer, and about equal to or greater thanthe dipole moment of the first polymer. In some embodiments, the firstand third polymers are the same polymer. In some embodiments, the firstand third polymers are different polymers. In some embodiments, thefirst polymer has a dipole moment greater than about 2 D. In someembodiments, the second polymer has a dipole moment lower than about 1D. In some embodiments, the third polymer has a dipole moment aboutequal to or greater than about 1 D. In some embodiments, the firstpolymer has a dipole moment greater than about 2 D, the second polymerhas a dipole moment lower than about 1 D, and the third polymer has adipole moment equal to or greater than about 1 D.

In some embodiments of the first method, the spinneret comprises aplurality of non-overlapping second channels inside the first channel,and therefore the prepared fibers comprise a first layer and a pluralityof non-overlapping second layers inside the first layer. In suchembodiments, at least one of the second layers has a dipole moment lowerthan about 1 D.

In some embodiments of the first method, the spinneret comprises aplurality of non-overlapping second channels inside the first channel,and a third channel inside each of the plurality of second channels.

Also provided herein, in one embodiment, is a nanofiber comprising afirst layer comprising a first polymer and a second layer inside thefirst layer and comprising a second polymer, wherein the first layer andthe second layer have different dipole moments.

In some embodiments, the first layer of the nanofiber has a dipolemoment greater than about 2 D and the second layer has a dipole momentlower than about 1 D.

In some embodiments, the nanofiber further comprise a third layer insidethe second layer, wherein the second layer and the third layer havedifferent dipole moments. In some embodiments, the first layer of thenanofiber has a dipole moment greater than about 2 D, and the secondpolymer has a dipole moment lower than about 1 D. In some embodiment,the first layer of the nanofiber has a dipole moment greater than about2 D, the second polymer has a dipole moment lower than about 1 D, andthe third layer has a dipole moment about equal to or greater than about1 D.

In some embodiments, the nanofiber comprises a plurality of secondlayers. In such embodiments, at least one of the second layers of thenanofiber has a dipole moment lower than about 1 D. In some embodiments,the nanofiber further comprises a third layer inside each of theplurality of second layers, and wherein each third layer has a differentdipole moment from the respective second layer.

Also provided herein, in one embodiment, is a second method of preparinga bicomponent or multicomponent nanofiber, wherein the method comprises:admixing a first polymer solution with a second polymer solution undersuitable conditions to prepare a mixture; and electrospinning themixture onto the surface of a substrate under conditions to allow thefirst polymer solution and the second polymer solution to maintain orseparate into different phases, thereby preparing a fibrous structurecomprising fibers having the first polymer and the second polymer inseparate portions.

In some embodiments of the second method, the first polymer and thesecond polymer have different dipole moments. In some embodiments, thefirst polymer has a dipole moment greater than about 2 D and the secondpolymer has a dipole moment lower than about 1 D

In some embodiments of the second method, the mixture comprises aboutequal volumes of the first polymer solution and the second polymersolution. In some embodiments, the ratio of the first polymer solutionto the second polymer solution in the mixture is about 100:1 to about1:100. In some embodiments, the ratio of the first polymer solution tothe second polymer solution in the mixture is about 1:100 to about 1:1,about 1:75 to about 1:1, about 1:50 to about 1:1, about 1:25 to about1:1, about 1:10 to about 1:1, about 1:5 to about 1:1, or about 1:1. Insome embodiments, the ratio of the first polymer solution to the secondpolymer solution in the mixture is about 100:1 to about 1:1, about 75:1to about 1:1, about 50:1 to about 1:1, about 25:1 to about 1:1, about10:1 to about 1:1, about 5:1 to about 1:1, or about 1:1. In someembodiments, the ratio of the first polymer solution to the secondpolymer solution in the mixture is about 1:1.

In some embodiments of the second method, at least part of the firstpolymer solution is phase separated from the second polymer solution. Insome embodiments of the second method, at least a portion of the mixtureis non-homogenous, and the at least part of the first polymer solutionis phase separated from the second polymer solution during theelectrospinning.

In some embodiments of the second method, the first polymer solution issubstantially evenly dispersed in the second polymer solution.

In some embodiments of the second method, the first polymer solutioncomprises a first therapeutic molecule. In some embodiments, the secondpolymer solution comprises a second therapeutic molecule. In someembodiments, the first therapeutic molecule requires a shorter releasetime in human patients than the second therapeutic molecule. In someembodiments, the second therapeutic molecule requires a shorter releasetime in human patients than the first therapeutic molecule.

Also provided herein, in one embodiment, is a third method of preparinga fibrous structure with an electrospinning device comprising aplurality of spinnerets, wherein the method comprises: supplying asolution of a first polymer to at least one of the spinnerets; supplyinga solution of a second polymer to at least another of the spinnerets;and electrospinning the solutions, through the respective spinnerets,onto the surface of a substrate, thereby preparing a fibrous structurecomprising fibers having different polymers.

In some embodiments of the third method, the first polymer and thesecond polymer have different dipole moments. In some embodiments, thefirst polymer has a dipole moment greater than about 2 D and the secondpolymer has a dipole moment lower than about 1 D

In some embodiments of the third method, the electrospinning devicecomprises at least a row of spinnerets, where at least one of thespinnerets in the row is connected to the first solution and at leastanother of the spinnerets in the row is connected to the secondsolution. In some embodiments, the electrospinning device comprises aplurality of rows of spinnerets, where all spinnerets in at least onerow are connected to the first solution and all spinnerets in at leastanother row are connected to the second solution.

Also provided herein, in one embodiment, is a fourth method of preparinga bicomponent or multicomponent nanofiber, wherein the method comprises:dipping a particle in a mixture of a first polymer solution and a secondpolymer solution; lifting the particle out of the mixture underconditions to allow the particle to be covered with the mixture; andapplying an electrical field between the particle and a collector toforce a nanofiber to form from the mixture on the particle and becollected on the collector, wherein the nanofiber comprises both thefirst polymer and the second polymer.

In some embodiments of the fourth method, at least part of the firstsolution has phase separation from the second solution. In someembodiments, at least part of the first polymer solution issubstantially located at the surface of the mixture.

In some embodiments of the fourth method, the particle has an exteriorrough surface. In some embodiments, the particle has a smooth exteriorsurface. In some embodiments, the particle is connected to one or moreparticles through a thread.

In some embodiments of the first, second, third, and fourth methodsdisclosed above, said methods may further comprises adding one or moreadditives by electrospinning, electrospraying, a spraying process, arolling process, etc.

Also provided herein, in one embodiment, is a fifth method of preparinga bicomponent or multifunctional nanofiber web, wherein the methodcomprises: forming a first layer of a nanofiber web on a substrate byelectrospinning system; and adding a functional layer on the first layerwith a second electrospinning system, spray system, or rolling system.

In some embodiments of the fifth method, the first layer comprises atleast two polymers having different dipole moments. In some embodiments,one of the polymers has a dipole moment greater than about 2 D andanother of the polymers has a dipole moment lower than about 1 D.

In some embodiments of the fifth method, the resulting multicomponentnanofiber web is configured to be useful for light emission, heatinsulation, heat resistance, sterilization, flame resistance,degradation, self-cleaning, anti-corrosion, or combinations thereof.

BRIEF DESCRIPTION OF THE FIGURES

Exemplary and non-limiting embodiments of the inventions may be morereadily understood by referring to the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of a bicomponent nanofiber comprising acoaxial (sheath-core) structure, according to one embodiment.

FIG. 2 is a cross-sectional view of a bicomponent nanofiber comprisingan “islands-in-sea” structure, according to one embodiment.

FIG. 3A is a side view of a bicomponent, fully coated nanofiber,according to one embodiment. FIGS. 3B-3C are two cross-sectional viewsof the bicomponent, fully coated nanofiber of FIG. 3A taken at twodifferent cross-sections thereof.

FIG. 4A is a side view of a bicomponent, partially coated nanofiber,according to one embodiment. FIGS. 4B-4D are three cross-sectional viewsof the bicomponent, partially coated nanofiber of FIG. 4A taken at threedifferent cross-sections thereof.

FIG. 5 is a side view of a bicomponent, dispersed nanofiber, accordingto one embodiment.

FIG. 6A is a side view of a bicomponent, aggregate nanofiber, accordingto one embodiment. FIGS. 6B-6D are three cross-sectional views of thebicomponent, aggregate nanofiber of FIG. 6A taken at three differentcross-sections thereof.

FIG. 7 is a cross-sectional view of a multicomponent nanofibercomprising a coaxial (sheath-core) structure, according to oneembodiment.

FIG. 8 is a cross-sectional view of a multicomponent nanofibercomprising a first type of “islands-in-sea” structure, according to oneembodiment.

FIG. 9 is a cross-sectional view of a multicomponent nanofibercomprising a second type “islands-in-sea” structure, according to oneembodiment.

FIG. 10A is a side view of a multicomponent, fully coated nanofiber,according to one embodiment. FIGS. 10B-10C are two cross-sectional viewsof the multicomponent, fully coated nanofiber of FIG. 10A taken at twodifferent cross-sections thereof.

FIG. 11A is a side view of a multicomponent, partially coated nanofiber,according to one embodiment. FIGS. 11B-11E are four cross-sectionalviews of the multicomponent, partially coated nanofiber of FIG. 11Ataken at four different cross-sections thereof.

FIG. 12 is a side view of a multicomponent, dispersed, according to oneembodiment.

FIG. 13A is a side view of a multicomponent, aggregate nanofiber,according to one embodiment. FIGS. 13B-13E are four cross-sectionalviews of the multicomponent, aggregate nanofiber of FIG. 13A taken atfour different cross-sections thereof.

FIGS. 14A-14K show various views of a system configured for formation ofbicomponent or multicomponent nanofibers, according to variousembodiments. For instance, FIGS. 14A-14B are cross-sectional and atop-down views, respectively, of an embodiment in which the systemcomprises at least one spinneret configured to form bicomponent, coaxial(“sheath-core”) nanofiber fibers. FIGS. 14C-14D are cross-sectional anda top-down views, respectively, of another embodiment in which thesystem comprises at least one spinneret configured to form bicomponent,islands-in-sea nanofibers. FIGS. 14E-14F are cross-sectional andtop-down views, respectively, of an embodiment in which the systemcomprises at least one spinneret configured to form multicomponent,coaxial (“sheath”) nanofibers. FIGS. 14G-14H are cross-sectional andtop-down views of an embodiment in which the system comprises at leastone spinneret configured to form a first type of multicomponent,islands-in-sea nanofibers. FIGS. 14I-14J are cross-sectional andtop-down views of an embodiment in which the system comprises at leastone spinneret configured to form a second type of multicomponent,islands-in-sea nanofiber. FIG. 14K is a cross-sectional view of anembodiment in which the system comprises at least one spinneretconfigured to form bicomponent or multicomponent fully coated, partiallycoated, dispersed, or aggregate nanofibers.

FIGS. 15A-15C are simplified schematics of a top-down electrospinningprocess (FIG. 15A), a bottom-up electrospinning process (FIG. 15B), anda vertical electrospinning process (FIG. 15C), according to variousembodiments.

FIGS. 16A-16C are cross-sectional, side views of a system for formingbicomponent or multicomponent nanofibers, where the system comprises asingle spinneret (FIG. 16A), a plurality of spinnerets (FIG. 16B), andat least two sets/groups of spinnerets configured to extrude differentmaterials or different combinations of materials (FIG. 16C), accordingto various embodiments.

FIGS. 17A-17B are cross-sectional, side views of a needleless (orneedle-free) system comprising a solution dipping component having arough surface (FIG. 17A) or a smooth surface (FIG. 17B). FIGS. 17C-17Dfurther show cross-sectional, side views of needleless extrusionelements comprising a thread connecting a plurality of features eachhaving a rough exterior surface (FIG. 17C) or a smooth exterior surface(FIG. 17D).

FIG. 18 is a simplified schematic of a system for producingmultifunctional nanofiber webs, according to one embodiment.

FIG. 19 is a flowchart of a method of preparing a bicomponent ormulticomponent nanofiber, according to one embodiment.

FIG. 20 is a flowchart of a method of preparing a bicomponent ormulticomponent nanofiber, according to another embodiment.

FIG. 21 is a flowchart of a method of preparing a fibrous structure withan electrospinning device comprising a plurality of spinnerets,according to one embodiment.

FIG. 22 is a flowchart of a method of preparing a bicomponent ormulticomponent nanofiber, according to yet another embodiment.

FIG. 23 is flowchart of a method of preparing a multifunctional web,according to one embodiment.

DETAILED DESCRIPTION

Described herein are systems, devices, and methods for producingbicomponent or multicomponent fibers.

1. Nanofibers

Provided herein, in some embodiments, is a nanofiber comprising at leasttwo polymers having different compositions and/or differentcharacteristics/properties from one another. For instance, in someembodiments, the at least two polymers may have different dipolemoments. In some embodiment, the difference between the dipole momentsof the at least two polymers may be at least about 1.0 D. In someembodiments, the difference between the dipole moments of the at leasttwo polymers may be at least about 1.0 D, at least about 1.5 D, at leastabout 2.0 D, at least about 2.5 D, at least about 3.0 D, at least about3.5 D, at least about 4.0 D, at least about 4.5 D, at least about 5.0 D,at least about 5.5 D, at least about 6.0 D, at least about 6.5 D, atleast about 7.0 D, at least about 7.5 D, at least about 8.0 D, at leastabout 8.5 D, at least about 9.0 D, at least about 9.5 D, or at leastabout 10.0 D. In some embodiments, the difference between the dipolemoments of the at least polymers may range from about 1.0 D to about10.0 D.

In some embodiments, at least a first of the polymers may have a dipolemoment about equal to or greater than about 2.0 D. In some embodiments,this first polymer may have a dipole moment equal to or greater thanabout 2.0 D, about 2.2 D, about 2.4 D, about 2.6 D, about 2.8 D, about3.0 D, about 3.2 D, about 3.4 D, about 3.6 D, about 3.8 D, about 4.0 D,about 4.2 D, about 4.4 D, about 4.6 D, about 4.8 D, about 5.0 D, about5.2 D, about 5.4 D, about 5.6 D, about 5.8 D, about 6.0 D, about 6.2 D,about 6.4 D, about 6.6 D, about 6.8 D, about 7.0 D, about 7.2 D, about7.4 D, about 7.6 D, about 7.8 D, about 8.0 D, about 8.2 D, about 8.4 D,about 8.6 D, about 8.8 D, about 9.0 D, about 9.2 D, about 9.4 D, about9.6 D, about 9.8 D, or about 10.0 D. In some embodiments, this firstpolymer may have a dipole moment ranging from about 2.0 D to about 10.0D.

Exemplary materials for the first polymer may include, but are notlimited to, polyimide, polyvinylidene fluoride, polyacrylonitrile,polyvinylpyrrolidone, and combinations thereof. In some embodiments, thefirst polymer may comprise polyimide having a dipole moment of about 6.1D. In some embodiments, the first polymer may comprisepolyvinylpyrrolidone having a dipole moment of about 2.3 D. In someembodiments, the first polymer may comprise polyvinylidene fluoridehaving a dipole moment of about 2.0 D. In some embodiment, the firstpolymer may comprise polyacrylonitrile having a dipole moment of about2.0 D. In some embodiment the first polymer may comprise any combination(e.g., at least two, at least three, or each) of polyimide,polyvinylidene fluoride, polyacrylonitrile, and polyvinylpyrrolidone.

In some embodiments, at least a second of the polymers may have a dipolemoment equal to or less than about 1.0 D. In some embodiments, thesecond polymer may have a dipole moment equal to or less than about 1.0D, about 0.9 D, about 0.8 D, about 0.7 D, about 0.6 D, about 0.5 D,about 0.4 D, about 0.3 D, about 0.2 D, about 0.1 D, about 0.5 D, orabout 0.0 D. In some embodiments, the second polymer may have a dipolemoment ranging from about 1.0 D to 0.0 D.

Exemplary materials for the second polymer may include, but are notlimited to, polypropylene, polyethylene, polystyrene,polytetrafluorethylene, or combinations thereof. In some embodiments,the second polymer may comprise polystyrene having a dipole moment ofabout 0.7 D. In some embodiments, the second polymer may comprisepolypropylene having a dipole moment of about 0.6 D. In someembodiments, the second polymer may comprise polyethylene having adipole moment of about 0.0 D. In some embodiments, the second polymermay comprise polytetrafluorethylene having a dipole moment of about 0.0D. In some embodiments, the second polymer may comprise any combination(e.g., at least two, at least three, or each) of polypropylene,polyethylene, polystyrene, and polytetrafluorethylene.

In some embodiments, the nanofiber may comprise at least a first polymerhaving a high dipole moment, and at least a second polymer having a lowdipole moment. By way of example, the first polymer may have a dipolemoment equal to or greater than about 2.0 D, and the second polymer mayhave a dipole moment less than about 1.0 D. The combination of the firstpolymer having a high dipole moment and the second polymer having a lowdipole moment may result in a nanofiber having unique structuralcharacteristics, properties, and/or functionalities. For instance, thefirst polymer having a high dipole moment may be hydrophilic, may havehigh surface energy, and/or be capable of retaining particulate matter.The second polymer having a low dipole moment may be hydrophilic, mayhave a low surface energy, and/or may be capable of grabbing particulatematter. Accordingly, in embodiments in which the nanofiber comprises atleast the first and second polymers having a high or low dipole moment,respectively, the nanofiber may exhibit superior mechanical properties,controlled hydrophobicity and/or hydrophilicity, controlled surfaceenergy, and/or a controlled capacity to retain and/or grab particulatematter. In some embodiments, the composition and/or arrangement of thepolymers in the nanofiber may be tailored/selected so as to produce adesired characteristic or functionality such as with respect to thedegree of hydrophobicity or hydrophilicity, surface energy, ability toretain and/or grab particulate matter, and/or the structural integrityof the nanofiber. Moreover, such nanofibers comprising at least thefirst and second polymers having a high or low dipole moment,respectively, may be uniquely suited for a variety of applications,including, but not limited to, applications in the printing industry,air filtration, oil separation, catalytic systems, etc.

In some embodiments, the nanofiber may be a bicomponent nanofibercomprising two polymers with different dipole moments from one another.In some embodiments, the nanofiber may be a multicomponent nanofibercomprising three or more polymers, where at least two of the polymershave different dipole moments from one another. In some embodiment, thebicomponent or multicomponent nanofiber may have a coaxial (sheath-core)structure, an “islands-in-sea” type structure, an aggregated structure,a dispersed structure, a partially coated structure, or a fully coatedstructure, as discussed in greater detail below.

It is of note that in some embodiments, the nanofiber may comprise atleast two polymers that differ with respect to properties other than, orin addition to, the respective dipole moments. For instance, in someembodiments, the at least two polymers may differ with respect to thedegree of adhesiveness of the polymers. For instance, in someembodiments, a first of the polymers may comprise an adhesive material,and the second of the polymers may comprise a non-adhesive material or amaterial that is less-adhesive than that of the first polymer.

Exemplary adhesive materials may include, but are not limited to, apressure sensitive adhesive polymer, a light sensitive adhesive polymer,a hot-melt adhesive polymer, or combinations thereof. Additionalexamples of adhesive materials include, but are not limited to,ethylene-vinyl acetate (EVA), polyolefins (PO), polyamides (PA),polyester, polyurethane (PU), an acrylic, bio-based acrylate, butylrubber, nitriles, silicone rubber, styrene butadiene rubber, naturalrubber latex, and combinations thereof.

Exemplary non-adhesive polymer materials may include, but are notlimited to, polypropylene, polyethylene, poly(ethylene oxide),polyethylene terephthalate, nylon, polyvinyl alcohol,polyvinylpyrrolidone, polyvinylidene fluoride, polystyrene,polypropylene, polyethylene, poly(ethylene oxide), polyethyleneterephthalate, polyacrylonitrile, polyimide, polyvinyl chloride,polycarbonate, polyurethane, polysulfone, polyactic acid,polytetrafluoroethylene, polybenzoxazoles, poly-aramid, poly(phenylenesulfide), poly-phenylene terephthalamide, polytetrafluoroethylene, orcombinations thereof.

a. Bicomponent Fibers

FIGS. 1-6D show various views of bicomponent nanofibers comprising afirst layer 102 and a second layer 104 arranged in different relativeconfigurations, according to various embodiments. The nanofibers, orfeatures thereof, in FIGS. 1-6D may be implemented in combination with,or as an alternative to, other nanofibers, or features thereof,described herein, such as those described with reference to otherembodiments and FIGS. The nanofibers of FIGS. 1-6D may additionally beutilized in any of the methods for making and/or using nanofibersdescribed herein. The nanofibers of FIGS. 1-6D may also be used invarious applications and/or in permutations, which may or may not benoted in the illustrative embodiments described herein. For instance,the nanofibers of FIGS. 1-6 may include more or less features/componentsthan those shown in FIGS. 1-6D, in some embodiments. Moreover, thenanofibers of FIGS. 1-6D are also not limited to the size, shape, numberof components/features, etc. specifically shown in FIGS. 1-6D. Further,as the nanofibers of FIGS. 1-6D may be variations of one another, likefeatures or components are assigned the same reference number.

In some embodiments, the first layer 102 of the bicomponent nanofibersmay comprise a first polymer, as disclosed herein, and the second layer104 of the bicomponent nanofibers may comprise a second polymer, asdisclosed herein. In some embodiments, the first polymer and the secondpolymer may have different dipole moments. For instance, in someembodiments, the first layer 102 may comprise a first polymer having ahigh dipole moment (e.g., equal to or greater than about 2.0 D), and thesecond layer 104 may comprise a second polymer having a low dipolemoment (e.g., less than about 1.0 D), as disclosed herein.

In some embodiments, the first and second polymers may differ withrespect to the degree of adhesiveness of the polymers. For instance, insome embodiments, the first polymer may comprise an adhesive material,and the second polymer may comprise a non-adhesive material or amaterial that is less-adhesive than that of the first polymer.

Exemplary adhesive materials may include, but are not limited to, apressure sensitive adhesive polymer, a light sensitive adhesive polymer,a hot-melt adhesive polymer, or combinations thereof. Additionalexamples of adhesive materials include, but are not limited to,ethylene-vinyl acetate (EVA), polyolefins (PO), polyamides (PA),polyester, polyurethane (PU), an acrylic, bio-based acrylate, butylrubber, nitriles, silicone rubber, styrene butadiene rubber, naturalrubber latex, and combinations thereof.

Exemplary non-adhesive polymer materials may include, but are notlimited to, polypropylene, polyethylene, poly(ethylene oxide),polyethylene terephthalate, nylon, polyvinyl alcohol,polyvinylpyrrolidone, polyvinylidene fluoride, polystyrene,polypropylene, polyethylene, poly(ethylene oxide), polyethyleneterephthalate, polyacrylonitrile, polyimide, polyvinyl chloride,polycarbonate, polyurethane, polysulfone, polyactic acid,polytetrafluoroethylene, polybenzoxazoles, poly-aramid, poly(phenylenesulfide), poly-phenylene terephthalamide, polytetrafluoroethylene, orcombinations thereof.

It is of note that the first polymer and the second polymer, asdisclosed herein, need not be limited to the first layer 102 and thesecond layer 104, respectively. As such, in some embodiments, the firstlayer 102 may comprise the second polymer, and the second layer 104 maycomprise the first polymer.

Referring now to FIG. 1, a cross-sectional view of a bicomponentnanofiber 100 comprising a coaxial (sheath-core) structure is shownaccording to one embodiment, where the cross-section is takenperpendicular to the longitudinal axis of the bicomponent nanofiber 100.As shown in FIG. 1, the bicomponent, coaxial nanofiber 100 comprises afirst layer 102 and a second layer 104 disposed within/inside the firstlayer 102. Stated another way, the bicomponent, coaxial nanofiber 100comprises a first layer 102 substantially surrounding/encircling thesecond layer 104.

In some embodiments, the first layer 102 of the bicomponent, coaxialnanofiber 100 may comprise the first polymer, as disclosed herein, andthe second layer 104 may comprise the second polymer, as disclosedherein. In some embodiment, however, the first layer 102 of thebicomponent, coaxial nanofiber 100 may comprise the second polymer, andthe second layer 104 may comprise the first polymer.

Referring now to FIG. 2, a cross-sectional view of a bicomponentnanofiber 200 comprising an “islands-in-sea” structure is shownaccording to one embodiment, where the cross-section is takenperpendicular to the longitudinal axis of the nanofiber 200. In someembodiments, the bicomponent, islands-in-sea nanofiber 200 comprises thefirst layer 102, and two or more “islands” comprising the second layer104 and which are disposed within/inside the “sea” of the first layer102. In the exemplary embodiment of FIG. 2, the bicomponent,islands-in-sea nanofiber 200 may comprise the first layer 102substantially surrounding/encircling four separate islands comprisingthe second layer 104. In some embodiments, however, the number of“islands” comprising the second layer 104 may be any integer numberequal to or greater than 2 (e.g., 3, 4, 5, 6, 7, 8, etc.).

In some embodiments, the first layer 102 of the bicomponent,islands-in-sea nanofiber 200 may comprise the first polymer, asdisclosed herein, and the second layer 104 may comprise the secondpolymer, as disclosed herein. However, in alternative embodiments, thefirst layer 102 of the bicomponent, islands-in-sea nanofiber 200 maycomprise the second polymer, and the second layer 104 may comprise thefirst polymer.

Referring now to FIG. 3A, a side view of a bicomponent, fully coatednanofiber 300 is shown according to one embodiment. As shown in FIG. 3A,the bicomponent, fully coated nanofiber 300 comprises the first layer102 substantially coating the second layer 104. The bicomponent, fullycoated nanofiber 300 is a similar to the bicomponent, coaxial nanofiber100 shown in FIG. 1, except that the bicomponent, fully coated nanofiber300 does not have a substantially uniform cross-section. For instance,while the second layer 104 is disposed within the first layer 102 alongthe length of the bicomponent, fully coated nanofiber 300, the shape andamount of the first layer 102 surrounding/encircling the second layer104 at one or more of the cross-sections of said nanofiber 300 may bedifferent.

By way of example, FIGS. 3B-3C provide two cross-sectional views of thebicomponent, fully coated nanofiber 300 taken at two differentcross-sections thereof. As evident in FIGS. 3B-3C, the cross-sectionalshape of the combination of the first and second layers 102, 104 vary atthese two different cross-sections of the nanofiber 300. In someembodiments, the cross-sectional shape of the combination of the firstand second layers 102, 104 may vary at each cross-section of thenanofiber 300.

In some embodiments, the first layer 102 of the bicomponent, fullycoated nanofiber 300 may comprise the first polymer, as disclosedherein, and the second layer 104 may comprise the second polymer, asdisclosed herein. However, in alternative embodiments, the first layer102 of the bicomponent, fully coated nanofiber 300 may comprise thesecond polymer, and the second layer 104 may comprise the first polymer.

As discussed previously, the first polymer may have a high dipolemoment, and the second polymer may have a low dipole moment, in someembodiments. By way of example, the first polymer may have a dipolemoment equal to or greater than about 2.0 D, and the second polymer mayhave a dipole moment less than about 1.0 D. As such, the first, highdipole moment polymer may have a high surface energy and/or be capableof retaining particulate matter. The second, low dipole moment polymer,may have a low surface energy and/or be capable of grabbing particulatematter. Accordingly, for the bicomponent nanofibers 100 (coaxial), 200(islands-in-sea), 300 (fully coated) in which the first, high dipolemoment polymer is present in the first layer 102 (the external layer),and the second, low dipole moment is present in the second layer(s) 104(the internal layer(s)), the resulting nanofibers can simultaneouslygrab and retain particulate matter, which may be particularly useful forfiltration applications.

Referring now to FIG. 4A, a side view of a bicomponent, partially coatednanofiber 400 is shown according to one embodiment. As shown in FIG. 4A,the bicomponent, partially coated nanofiber 400 comprises the firstlayer 102 as a coating on one or more portions of the second layer 104.In contrast to the bicomponent, fully coated nanofiber 300 of FIGS.3A-3C, the first layer 102 of the bicomponent, partially coatednanofiber 400 does not coat (e.g. surround/encircle) all portions of thesecond layer 104.

However, similar to the bicomponent, fully coated nanofiber 300 of FIGS.3A-3C, the bicomponent, partially coated nanofiber 400 does not have auniform cross-section. For instance, one or more cross-sections of thebicomponent, partially coated nanofiber 400 may differ with respect tothe shape and amount of the first layer 102 surrounding/encircling theinnermost second layer 104, as shown, e.g., in the two cross-sectionalviews provided in FIGS. 4B-4C. As also shown in FIG. 4D, there may beone or more regions of the bicomponent, partially coated nanofiber 400that include solely the second layer 104 with no coating of the firstlayer 102 thereon.

In some embodiments, the first layer 102 of the bicomponent, partiallycoated nanofiber 400 may comprise the first polymer, as disclosedherein, and the second layer 104 may comprise the second polymer, asdisclosed herein. However, in alternative embodiments, the first layer102 of the bicomponent, partially coated nanofiber 400 may comprise thesecond polymer, and the second layer 104 may comprise the first polymer.

Referring now to FIG. 5, a side view of a bicomponent, dispersednanofiber 500 is shown according to one embodiment. As shown in FIG. 5,the bicomponent, dispersed nanofiber 500 comprises a dispersion of thefirst layer 102 and the second layer 104. In some embodiments, thebicomponent, dispersed nanofiber 500 may comprise a uniform dispersionof the first layer 102 and the second layer 104.

In the embodiment of FIG. 5, the first layer 102 may be dispersedwithin/throughout the second layer 102. In such embodiments, the ratioof the second layer 104 to the first layer 102 is about 100:1 to about1:1. In some embodiments, the ratio of the second layer 104 to the firstlayer 102 is about 100:1 to about 1:1, about 75:1 to about 1:1, about50:1 to about 1:1, about 25:1 to about 1:1, about 10:1 to about 1:1,about 5:1 to about 1:1, or about 1:1. In some embodiments, the ratio ofthe second layer 104 to the first layer 102 is about 20:1 to about 5:1.

In some embodiments, the first layer 102 of the bicomponent, dispersednanofiber 500 may comprise the first polymer, as disclosed herein, andthe second layer 104 may comprise the second polymer, as disclosedherein. However, in alternative embodiments, the first layer 102 of thebicomponent, dispersed nanofiber 500 may comprise the second polymer,and the second layer 104 may comprise the first polymer.

Referring now to FIG. 6A, a side view of a bicomponent, aggregatenanofiber 600 is shown according to one embodiment. As shown in FIG. 6A,the bicomponent, aggregate nanofiber 600 comprises the first layer 102dispersed within one or more portions of the second layer 104. Incontrast to the bicomponent, dispersed nanofiber 500 of FIG. 5, thefirst layer 102 of the bicomponent, aggregate nanofiber 600 is dispersedonly within certain portions, and not throughout substantially theentirety, of the second layer 104.

The bicomponent, aggregate nanofiber 600 may not have a uniformcross-section. For instance, one or more cross-sections of thebicomponent, aggregate nanofiber 600 may differ with respect to theshape and amount of the first layer 102 dispersed within the secondlayer 104, as shown, e.g., in the two cross-sectional views provided inFIGS. 6B-6C. As also shown in FIG. 6D, there may be one or more regionsof the bicomponent, aggregate nanofiber 600 that include solely thesecond layer 104 with none of the first layer 102 dispersed within.

In alternative embodiments, the second layer 104 of the bicomponent,aggregate nanofiber 600 may be dispersed within one or more portions,but not the throughout the entirety, of the first layer 102.

In some embodiments, the first layer 102 of the bicomponent, aggregatenanofiber 600 may comprise the first polymer, as disclosed herein, andthe second layer 104 may comprise the second polymer. However, inalternative embodiments, the first layer 102 of the bicomponent,aggregate nanofiber 600 may comprise the second polymer, and the secondlayer 104 may comprise the first polymer.

As discussed previously, the first polymer may have a high dipole moment(e.g., equal to or greater than about 2.0 D) and be hydrophilic, whereasthe second polymer may have a low dipole moment (e.g., less than about1.0 D) and be hydrophobic. In such embodiments, the bicomponentnanofibers 400 (partially coated), 500 (dispersed), 600 (aggregate) maybe used as a drug carrier or other carriers for fine chemistry, wherethe first, hydrophilic polymer with the high dipole moment will releasea drug or chemicals quickly in an aqueous process, and the second,hydrophobic polymer with the low dipole moment will release the drug orchemicals slowly in an aqueous process. Accordingly, said bicomponentnanofibers 400, 500, 600 coupled to at least two drugs or chemicals cansuccessively release the at least two drugs or chemicals in an aqueousprocess.

In some embodiments, the first, hydrophilic polymer and the second,hydrophobic polymer may be coupled to different drugs (therapeuticmolecules) or chemicals. For instance, in one exemplary embodiment, thefirst, hydrophilic polymer may be coupled to a first therapeuticmolecule and the second, hydrophobic polymer may be coupled to a secondtherapeutic molecule, where the first therapeutic molecule may require ashorter release time in human patients as compared to the secondtherapeutic molecule. In some embodiments, the first, hydrophilicpolymer and the second, hydrophobic polymer may be coupled to differentdrugs or chemicals. For instance, in one exemplary embodiment, thefirst, hydrophilic polymer may be coupled to a first therapeuticmolecule and the second, hydrophobic polymer may be coupled to a secondtherapeutic molecule, where the second therapeutic molecule may requirea shorter release time in human patients as compared to the firsttherapeutic molecule.

b. Multicomponent Nanofibers

FIGS. 7-13E show various views of multicomponent nanofibers comprisingat least a first layer 102, at least a second layer 104, and at leastthird layer 106 arranged in different relative configurations, accordingto various embodiments. The nanofibers, or features thereof, in FIGS.7-13E may be implemented in combination with, or as an alternative to,other nanofibers, or features thereof, described herein, such as thosedescribed with reference to other embodiments and FIGS. The nanofibersof FIGS. 7-13E may additionally be utilized in any of the methods formaking and/or using nanofibers described herein. The nanofibers of FIGS.7-13E may also be used in various applications and/or in permutations,which may or may not be noted in the illustrative embodiments describedherein. For instance, the nanofibers of FIGS. 7-13E may include more orless features/components than those shown in FIGS. 7-13E, in someembodiments. Moreover, the nanofibers of FIGS. 7-13E are also notlimited to the size, shape, number of components/features, etc.specifically shown in FIGS. 7-13E. Further, as the nanofibers of FIGS.7-13E may be variations of one another, like features or components areassigned the same reference number.

In some embodiments, the first layer 102 of the multicomponentnanofibers may comprise a first polymer, as disclosed herein, and thesecond layer 104 may comprise a second polymer, as disclosed herein.Additionally, the multicomponent nanofibers may comprise a third layercomprising a third polymer.

In some embodiments, at least two of the first, second, and thirdpolymers may have different dipole moments from one another. In someembodiments, the first, second, and third polymers may each havedifference dipole moments from one another.

In some embodiments, the first polymer may have a dipole moment that isgreater than the dipole moment of at least the second polymer. In someembodiments, the first polymer may have a dipole moment that is greaterthan the second polymer and the third polymer. In some embodiments, thethird polymer may have a dipole moment that is greater than the secondpolymer, but less than the first polymer. In some embodiments, therelative relationship between the dipole moments (μ) of the firstpolymer (μ₁), the second polymer (μ₂), and the third polymer (μ₃) may beexpressed according to any of the following:

μ₁≥μ₂ and/or μ₃;

μ₁≥μ₂≥μ₃;

μ₁≥μ₃≥μ₂;

μ₁≈μ₃≥μ₂;

μ₃≥μ₁≥μ₂;

In some embodiments, the first and third polymers may each independentlyhave a high dipole moment, and the second polymer may have a low dipolemoment. In some embodiments, the first and third polymers may eachindependently have a high dipole moment, and the second polymer may havea low dipole moment, where the high dipole moments of the first andthird polymer are about equal to one another. In some embodiments, thefirst and third polymers may each independently have a high dipolemoment provided that the dipole moment of the first polymer is greaterthan that of the third polymer, and the second polymer may have a lowdipole moment. In some embodiments, the first and third polymers mayeach independently have a high dipole moment provided that dipole momentof the third polymer is greater than that of the first polymer, and thesecond polymer may have a low dipole moment.

In some embodiments, the first polymer may have a dipole moment greaterthan about 2.0 D. In some embodiments, the second polymer may have adipole moment less than about 1 D. In some embodiments, the thirdpolymer may have a dipole moment equal to or greater than about 1 D. Insome embodiments, the first polymer may have a dipole moment greaterthan about 2.0 D, the second polymer may have a dipole moment less thanabout 1 D, and the third polymer may have a dipole moment equal to orgreater than about 1 D.

In some embodiments, the first, second, and third polymers may differwith respect to the degree of adhesiveness of the polymers. Forinstance, in some embodiments, the first polymer may comprise anadhesive material, and the second polymer and/or third polymer may eachindependently comprise a non-adhesive material or a material that isless-adhesive than that of the first polymer. In some embodiments, thefirst polymer and the third polymer may comprise an adhesive material(that may be the same or different from one another), and the secondpolymer may comprise a non-adhesive material or a material that isless-adhesive than that of the first and third polymers. In someembodiments, the first, second, and third polymers may comprise adifferent adhesive polymer or a different adhesive polymer compositionfrom one another.

As discussed previously, exemplary adhesive materials may include, butare not limited to, a pressure sensitive adhesive polymer, a lightsensitive adhesive polymer, a hot-melt adhesive polymer, or combinationsthereof. Additional examples of adhesive materials include, but are notlimited to, ethylene-vinyl acetate (EVA), polyolefins (PO), polyamides(PA), polyester, polyurethane (PU), an acrylic, bio-based acrylate,butyl rubber, nitriles, silicone rubber, styrene butadiene rubber,natural rubber latex, and combinations thereof.

Exemplary non-adhesive polymer materials may also include, but are notlimited to, polypropylene, polyethylene, poly(ethylene oxide),polyethylene terephthalate, nylon, polyvinyl alcohol,polyvinylpyrrolidone, polyvinylidene fluoride, polystyrene,polypropylene, polyethylene, poly(ethylene oxide), polyethyleneterephthalate, polyacrylonitrile, polyimide, polyvinyl chloride,polycarbonate, polyurethane, polysulfone, polyactic acid,polytetrafluoroethylene, polybenzoxazoles, poly-aramid, poly(phenylenesulfide), poly-phenylene terephthalamide, polytetrafluoroethylene, orcombinations thereof.

Referring now to FIG. 7, a cross-sectional view of a multicomponentnanofiber 700 comprising a coaxial (sheath-core) structure is shownaccording to one embodiment, where the cross-section is takenperpendicular to the longitudinal axis of the multicomponent nanofiber700. As shown in FIG. 7, the multicomponent, coaxial nanofiber 700comprises an outer, first layer 102, an intermediate, second layer 104,and an innermost, third layer 106.

In some embodiments, the first layer 102 of the multicomponent, coaxialnanofiber 700 may comprise the first polymer, as disclosed herein, thesecond layer 104 may comprise the second polymer, as disclosed herein,and the third layer 106 may comprise the third polymer, as disclosedherein.

Referring now to FIG. 8, a cross-sectional view of a multicomponentnanofiber 800 comprising a first type of “islands-in-sea” structure isshown according to one embodiment, where the cross-section is takenperpendicular to the longitudinal axis of the nanofiber 800. In someembodiments, the multicomponent, islands-in-sea nanofiber 800 comprisesthe first layer 102 substantially surrounding/encircling two or more“islands,” where at least one of the islands comprises the second layer104 and at least another of the islands comprises the third layer 106.In the exemplary embodiment of FIG. 8, the multicomponent,islands-in-sea nanofiber 800 may comprise the first layer 102substantially surrounding/encircling four separate islands, where two ofthe islands comprise the second layer 104, and two of the islandscomprise the third layer 106. In some embodiments, however, the numberof “islands” comprising the second and third layers 104, 106 mayindependently be any integer number equal to or greater than 2 (e.g., 3,4, 5, 6, 7, 8, etc.). Moreover, in some embodiments, the multicomponent,islands-in-sea nanofiber 800 may comprise one or more additional islandseach independently comprising an additional polymer material (e.g., apolymer material different than the first, second, and third polymersdisclosed herein).

In some embodiments, the first layer 102 of the multicomponent,islands-in-sea nanofiber 800 may comprise the first polymer, asdisclosed herein, the second layer 104 may comprise the second polymer,as disclosed herein, and the third layer 106 may comprise the thirdpolymer, as disclosed herein.

Referring now to FIG. 9, a cross-sectional view of a multicomponentnanofiber 900 comprising a second type of “islands-in-sea” structure isshown according to another embodiment, where the cross-section is takenperpendicular to the longitudinal axis of the nanofiber 900. In someembodiments, the multicomponent, islands-in-sea nanofiber 900 comprisesthe first layer 102 substantially surrounding/encircling at least two“islands,” where each island comprises the second layer 104substantially surrounding/encircling the third layer 106. In theexemplary embodiment of FIG. 9, the multicomponent, islands-in-seananofiber 900 may comprise the first layer 102 substantiallysurrounding/encircling four separate islands comprising the second andthird layers 104, 106. In some embodiments, however, the number of“islands” comprising the second and third layers 104, 106 may be anyinteger number equal to or greater than 2 (e.g., 3, 4, 5, 6, 7, 8,etc.). Moreover, in some embodiments, the multicomponent, islands-in-seananofiber 900 may comprise one or more additional layers disposed withinthe third layer 106, where each additional layer independentlycomprising an additional polymer material (e.g., a polymer materialdifferent from the first, second, and third polymers disclosed herein).

In some embodiments, the first layer 102 of the multicomponent,islands-in-sea nanofiber 900 may comprise the first polymer, asdisclosed herein, the second layer 104 may comprise the second polymer,as disclosed herein, and the third layer 106 may comprise the thirdpolymer, as disclosed herein.

Referring now to FIG. 10A, a side view of a multicomponent, fully coatednanofiber 900 is shown according to one embodiment. As shown in FIG.10A, the multicomponent, fully coated nanofiber 1000 comprises thefirst, second, and third layers 102, 104, 106, where the first layer 102substantially coats the second layer 104, and the second layer 104substantially coats the third layer 106. The multicomponent, fullycoated nanofiber 1000 is similar to the multicomponent, coaxialnanofiber 700 shown in FIG. 7, except that the multicomponent, fullycoated nanofiber 1000 does not have a substantially uniformcross-section. For instance, one or more cross-sections of themulticomponent, fully coated nanofiber 1000 may differ with respect tothe shape and amount of the first and second layers 102, 104, as shown,e.g., in the two cross-sectional views provided in FIGS. 10B-10C. Insome embodiments, the cross-sectional shape of the combination of thefirst, second, and third layers 102, 104, 106 may vary at eachcross-section of the nanofiber 1000.

In some embodiments, the first layer 102 of the multicomponent, fullycoated nanofiber 1000 may comprise the first polymer, as disclosedherein, the second layer 104 may comprise the second polymer, asdisclosed herein, and third layer 106 may comprise the third polymer, asdisclosed herein.

As discussed previously, the first polymer and the third polymer mayeach independently have a high dipole moment, and the second polymer mayhave a low dipole moment), in some embodiments. By way of example, thefirst polymer may have a dipole moment equal to or greater than about2.0 D, the second polymer may have a dipole moment less than about 1.0D, and third polymer may have a dipole moment equal to or greater thanabout 1.0 D. As such, the first high dipole moment polymer tends to havehigher surface area, thus resulting in a high capability to retainparticulate matter. The second, low dipole moment polymer may have acapability for grabbing particulate matters. The third high dipolemoment polymer tends to be charged, thus resulting in a highelectrostaticity for grabbing and retaining particulate matters.Accordingly, for the multicomponent nanofibers 700 (coaxial), 800(islands-in-sea), 900 (islands-in-sea), 1000 (fully coated) in which thefirst, high dipole moment polymer is present in the first layer 102 (theexternal layer), the second, low dipole moment polymer is present in thesecond layer(s) 104 (the internal layer(s)), and the third, high dipolemoment polymer is present in the third layer 106, the resultingnanofibers can simultaneously grab and retain particulate matter, whichmay be particularly useful for filtration applications.

Referring now to FIG. 11A, a side view of a multicomponent, partiallycoated nanofiber 1100 is shown according to one embodiment. As shown inFIG. 11A, the multicomponent, partially coated nanofiber 1100 comprisethe innermost, third layer 106 partially coated by the first layer 102or the second layer 104 or a combination thereof. In contrast to themulticomponent, fully coated nanofiber 1000 of FIGS. 10A-10C, the firstlayer 102 and the second layer 104 of the multicomponent, partiallycoated nanofiber 1100 does not coat (e.g. surround/encircle) allportions of the innermost third layer 106.

However, similar to the multicomponent, fully coated nanofiber 1000 ofFIGS. 10A-10C, the multicomponent, partially coated nanofiber 1100 doesnot have a uniform cross-section. For instance, one or morecross-sections of the multicomponent, partially coated nanofiber 1100may differ with respect to the shape and amount of the first layer 102and/or the second layer 106 surrounding/encircling the innermost thirdlayer 106, as shown, e.g., in the three cross-sectional views providedin FIGS. 11B-11D. As also shown in FIG. 11E, there may be one or moreregions of the multicomponent, partially coated nanofiber 1100 thatinclude solely the third layer 106 with no coating of the first layer102 and/or the second layer 104 thereon.

In some embodiments, the first layer 102 of the multicomponent,partially coated nanofiber 1100 may comprise the first polymer, asdisclosed herein, the second layer 104 may comprise the second polymer,as disclosed herein, and the third layer 106 may comprise the thirdpolymer, as disclosed herein.

Referring now to FIG. 12, a side view of a multicomponent, dispersednanofiber 1200 is shown according to one embodiment. As shown in FIG.12, the bicomponent, dispersed nanofiber 1200 comprises a dispersion ofthe first layer 102, the second layer 104, and the third layer 106. Insome embodiments, the bicomponent, dispersed nanofiber 1200 may comprisea uniform dispersion of the first layer 102, the second layer 104, andthe third layer 106. In the particular embodiment of FIG. 12, the firstand second layer 102, 104 are dispersed within the third layer 106.

In some embodiments, the first layer 102 of the multicomponent,dispersed nanofiber 1200 may comprise the first polymer, as disclosedherein, the second layer 104 may comprise the second polymer, asdisclosed herein, and the third layer 106 may comprise the thirdpolymer, as disclosed herein.

Referring now to FIG. 13A, a side view of a multicomponent, aggregatenanofiber 1300 is shown according to one embodiment. As shown in FIG.13A, the multicomponent, aggregate nanofiber 1300 comprises the firstlayer 102 or the second layer 104 or a combination thereof dispersedwithin one or more portions of the third layer 106. In contrast to themulticomponent, dispersed nanofiber 1200 of FIG. 12, the first layer 102and/or the second layer 104 of the multicomponent, aggregate nanofiber1300 is dispersed only within certain portions, and not throughoutsubstantially the entirety, of the third layer 106.

The multicomponent, aggregate nanofiber 1300 does not have a uniformcross-section. For instance, one or more cross-sections of themulticomponent, aggregate nanofiber 1300 may differ with respect to theshape and amount of the first layer 102 and/or the second layer 104dispersed within the third layer 106, as shown, e.g., in the threecross-sectional views provided in FIGS. 13B-13D. As also shown in FIG.13E, there may be one or more regions of the multicomponent, aggregatenanofiber 1300 that include solely the third layer 106 with none of thefirst layer 102 dispersed within.

In some embodiments, the first layer 102 of the multicomponent,aggregate nanofiber 1300 may comprise the first polymer, as disclosedherein, the second layer 104 may comprise the second polymer, asdisclosed herein, and the third layer 106 may comprise the thirdpolymer, as disclosed herein.

As discussed previously, the first polymer and the third polymers mayeach independently have a high dipole moment (e.g., the first polymermay have a dipole moment equal to or greater than about 2.0 D, and thethird polymer may have a dipole moment equal to or greater than about1.0 D) and be hydrophilic, whereas the second polymer may have a lowdipole moment (e.g., less than about 1.0 D) and be hydrophobic. In suchembodiments, the multicomponent nanofibers 1100 (partially coated), 1200(dispersed), 1300 (aggregate) may be used as a drug carrier or othercarriers for fine chemistry, where the first and third hydrophilicpolymers with the high dipole moment will release a drug or chemicalsquickly in an aqueous process, and the second, hydrophobic polymer withthe low dipole moment will release the drug or chemicals slowly in anaqueous process. Accordingly, said multicomponent nanofibers 1100, 1200,1300 attached to at least two drugs or chemicals can successivelyrelease the at least two drugs or chemicals in an aqueous process.

2. Systems

Provided herein are various, customizable systems configured to producethe nanofibers disclosed herein (e.g., the nanofibers shown in FIGS.1-13E).

a. Spinneret Systems

For instance, FIGS. 14A-14K describe a system 1400 comprising at leastone spinneret 1402 configured to form bicomponent or multicomponentnanofibers. In some embodiments, the materials to be formed into thedual or multicomponent nanofibers exit, or are drawn from, the spinneret1402 toward a substrate 1404 to form a layer 1406 of the dual ormulticomponent nanofibers thereon. In some embodiments, the substrate1404 may be conductive. In some embodiments, the substrate 1404 may benon-conductive.

FIGS. 14A-14B provide a cross-sectional and a top-down view,respectively, of an embodiment in which the system 1400 comprises atleast one spinneret 1402 a configured to form bicomponent, coaxial(“sheath-core”) nanofibers (such as described, e.g., in FIG. 1). The atleast one spinneret 1402 a may comprise at least one of a first channel1408 having a first surface 1410 a in fluid communication with a firstsource (not shown) of a first polymer 1412 (e.g., solution or meltcomprising the first polymer), and a second surface 1414 a from with thefirst polymer 1412 is extruded. The at least one spinneret 1402 a mayfurther comprise at least one of a second channel 1416 having a firstsurface 1410 b in fluid communication with a second source (not shown)of a second polymer 1418 (e.g., a solution or melt comprising the secondpolymer), and a second surface 1414 b from which the second polymer 1418is extruded. In some embodiments, the first and second channels 1408,1416 may simultaneously extrude the first and second polymer 1412, 1418to form bicomponent, coaxial nanofibers, which may travel, or are drawn,toward the substrate 1404 to form the layer 1406 thereupon.

In some embodiments, the first channel 1408 may be positioned along oneor more portions of the outer periphery of the spinneret 1402 a, whereasthe second channel 1416 may be positioned within an interior portion ofthe spinneret 1402 a. In some embodiments, the first channel 1408 may beconcentrically disposed about the inner, second channel 1416.

In some embodiments, the second channel 1416 may have a cross-sectionalshape that is substantially rounded (e.g., circular, elliptical, etc.).In some embodiments, the first channel 1408 may have a cross sectionalshape that is substantially rounded (e.g., circular, elliptical, etc.),square, rectangular, irregular, or other such suitable shape as wouldbecome apparent to a skilled artisan upon reading the presentdisclosure. In some embodiments, both the first and second channels1408, 1416 may have a rounded (e.g., circular, elliptical, etc.)cross-sectional shape.

As disclosed herein, the first polymer 1412 and the second polymer 1418may have different dipole moments, in some embodiments. For instance, insome embodiments, the first polymer 1412 may have a high dipole moment(e.g., equal to or greater than about 2.0 D), and the second polymer1418 may a low dipole moment (e.g., less than about 1.0 D), as disclosedherein.

In some embodiments, the first and second polymers 1412, 1418 may differwith respect to the degree of adhesiveness of the polymers. Forinstance, in some embodiments, the first polymer 1412 may comprise anadhesive material, and the second polymer 1418 may comprise anon-adhesive material or a material that is less-adhesive than that ofthe first polymer 1412.

Exemplary adhesive materials may include, but are not limited to, apressure sensitive adhesive polymer, a light sensitive adhesive polymer,a hot-melt adhesive polymer, or combinations thereof. Additionalexamples of adhesive materials include, but are not limited to,ethylene-vinyl acetate (EVA), polyolefins (PO), polyamides (PA),polyester, polyurethane (PU), an acrylic, bio-based acrylate, butylrubber, nitriles, silicone rubber, styrene butadiene rubber, naturalrubber latex, and combinations thereof.

Exemplary non-adhesive polymer materials may include, but are notlimited to, polypropylene, polyethylene, poly(ethylene oxide),polyethylene terephthalate, nylon, polyvinyl alcohol,polyvinylpyrrolidone, polyvinylidene fluoride, polystyrene,polypropylene, polyethylene, poly(ethylene oxide), polyethyleneterephthalate, polyacrylonitrile, polyimide, polyvinyl chloride,polycarbonate, polyurethane, polysulfone, polyactic acid,polytetrafluoroethylene, polybenzoxazoles, poly-aramid, poly(phenylenesulfide), poly-phenylene terephthalamide, polytetrafluoroethylene, orcombinations thereof.

FIGS. 14C-14D provide a cross-sectional and a top-down view,respectively, of another embodiment in which the system 1400 comprisesat least one spinneret 1402 b configured to form bicomponent,islands-in-sea nanofibers (such as described, e.g., in FIG. 2). As shownin the top down view provided in FIG. 14D, the at least one spinneret1402 b may, in some embodiments, comprise four of the second channels1416 in spaced relation with one another, and further disposed within aninterior portion of the first channel 1408. In some embodiments, thefirst and second channels 1408, 1416 may simultaneously extrude thefirst and second polymers 1412, 1418, respectively, to form bicomponent,islands-in-sea nanofibers, which may travel, or be drawn, toward thesubstrate 1404 to form the single layer 1420 thereupon.

It is of note that the at least one spinneret 1402 b of FIGS. 14C-14D isnot limited to the number or configuration of the second channels 1416.Rather, the at least one spinneret 1402 b may include any number orconfiguration of the second channels 1416 so as to achieve a desirednumber and configuration of the second polymer 1416 “islands” disposedwithin the “sea” of the first polymer 1412.

In some embodiments, the second channel 1416 of spinneret 1402 b mayhave a cross-sectional shape that is substantially rounded (e.g.,circular, elliptical, etc.). In some embodiments, the first channel 1408of spinneret 1402 b may have a cross sectional shape that issubstantially rounded (e.g., circular, elliptical, etc.), square,rectangular, irregular, or other such suitable shape as would becomeapparent to a skilled artisan upon reading the present disclosure. Insome embodiments, both the first and second channels 1408, 1416 ofspinneret 1402 b may have a rounded (e.g., circular, elliptical, etc.)cross-sectional shape.

FIGS. 14E-14F provide a cross-sectional and top-down view, respectively,of an embodiment in which the system 1400 comprises at least onespinneret 1402 c configured to form multicomponent, coaxial (“sheath”)nanofibers (such as described, e.g., in FIG. 7). The at least onespinneret 1402 c may comprise at least the first channel 1408 and atleast the second channel 1416 configured to extrude the first polymer1412 and the second material 1418, respectively, as described above. Theat least one spinneret 1402 b may further comprise at least a thirdchannel 1422 having a first surface 1410 c in fluid communication with athird source (not shown) of a third polymer 1424 (e.g., a solution ormelt comprising the third polymer), and a second surface 1414 c fromwhich the third polymer 1424 is extruded. In some embodiments, thefirst, second, and third channel 1408, 1416, 1422 may simultaneouslyextrude the first, second, and third polymers 1412, 1418, 1424,respectively to form multicomponent, coaxial nanofibers, which maytravel, or be drawn, toward the substrate 1404 to form the single layer1406 thereupon.

As disclosed herein, at least two of the first, second, and thirdpolymers may have different dipole moments from one another. In someembodiments, the first, second, and third polymers may each havedifference dipole moments from one another.

In some embodiments, the first polymer may have a dipole moment that isgreater than the dipole moment of at least the second polymer. In someembodiments, the first polymer may have a dipole moment that is greaterthan the second polymer and the third polymer. In some embodiments, thethird polymer may have a dipole moment that is greater than the secondpolymer, but less than the first polymer. In some embodiments, therelative relationship between the dipole moments (μ) of the firstpolymer (μ₁), the second polymer (μ₂), and the third polymer (μ₃) may beexpressed according to any of the following:

μ₁≥μ₂ and/or μ₃;

μ₁≥μ₂≥μ₃;

μ₁≥μ₃≥μ₂;

μ₁≈μ₃≥μ₂;

μ₃≥μ₁≥μ₂;

In some embodiments, the first and third polymers may each independentlyhave a high dipole moment, and the second polymer may have a low dipolemoment. In some embodiments, the first and third polymers may eachindependently have a high dipole moment, and the second polymer may havea low dipole moment, where the high dipole moments of the first andthird polymer are about equal to one another. In some embodiments, thefirst and third polymers may each independently have a high dipolemoment provided that dipole moment of the first polymer is greater thanthat of the third polymer, and the second polymer may have a low dipolemoment. In some embodiments, the first and third polymers may eachindependently have a high dipole moment provided that dipole moment ofthe third polymer is greater than that of the first polymer, and thesecond polymer may have a low dipole moment.

In some embodiments, the first polymer may have a dipole moment greaterthan about 2.0 D. In some embodiments, the second polymer may have adipole moment less than about 1 D. In some embodiments, the thirdpolymer may have a dipole moment equal to or greater than about 1 D. Insome embodiments, the first polymer may have a dipole moment greaterthan about 2.0 D, the second polymer may have a dipole moment less thanabout 1 D, and the third polymer may have a dipole moment equal to orgreater than about 1 D.

In some embodiments, the first, second, and third polymers may differwith respect to the degree of adhesiveness of the polymers. Forinstance, in some embodiments, the first polymer may comprise anadhesive material, and the second polymer and/or third polymer may eachindependently comprise a non-adhesive material or a material that isless-adhesive than that of the first polymer. In some embodiments, thefirst polymer and the third polymer may comprise an adhesive material(that may be the same or different from one another), and the secondpolymer may comprise a non-adhesive material or a material that isless-adhesive than that of the first and third polymers. In someembodiments, the first, second, and third polymers may comprise adifferent adhesive polymer or a different adhesive polymer compositionfrom one another.

As discussed previously, exemplary adhesive materials may include, butare not limited to, a pressure sensitive adhesive polymer, a lightsensitive adhesive polymer, a hot-melt adhesive polymer, or combinationsthereof. Additional examples of adhesive materials include, but are notlimited to ethylene-vinyl acetate (EVA), polyolefins (PO), polyamides(PA), polyester, polyurethane (PU), an acrylic, bio-based acrylate,butyl rubber, nitriles, silicone rubber, styrene butadiene rubber,natural rubber latex, and combinations thereof.

Exemplary non-adhesive polymer materials may also include, but are notlimited to, polypropylene, polyethylene, poly(ethylene oxide),polyethylene terephthalate, nylon, polyvinyl alcohol,polyvinylpyrrolidone, polyvinylidene fluoride, polystyrene,polypropylene, polyethylene, poly(ethylene oxide), polyethyleneterephthalate, polyacrylonitrile, polyimide, polyvinyl chloride,polycarbonate, polyurethane, polysulfone, polyactic acid,polytetrafluoroethylene, polybenzoxazoles, poly-aramid, poly(phenylenesulfide), poly-phenylene terephthalamide, polytetrafluoroethylene, orcombinations thereof.

With continued reference to FIGS. 14E-14F, the third channel 1422, insome embodiments, may be positioned within the innermost region of thespinneret 1402 c, the second channel 1416 may surround one or moreportions of the third channel 1422, and the first channel 1408 maysurround one or more portions of the second channel 1416. In someembodiments, the second channel 1416 may be concentrically disposedabout the innermost third channel 1422, and the first channel 1408 maybe concentrically disposed about the middle, second channel 1416.

In some embodiments, the second channel 1416 and/or the third channel1422 may each independently have a cross-sectional shape that issubstantially rounded (e.g., circular, elliptical, etc.). Moreover, asnoted previously, the first channel 1408 may have a cross sectionalshape that is substantially rounded (e.g., circular, elliptical, etc.),square, rectangular, irregular, or other such suitable shape, in someembodiments. In some embodiments, each of the first, second, and thirdchannels 1408, 1416, 1422 may have a rounded (e.g., circular,elliptical, etc.) cross-sectional shape.

In some embodiments, the second and third channels 1416, 1422 may not beconcentrically disposed. For instance, FIGS. 14G-1411 provide across-sectional and a top-down view, respectively, of another embodimentin which the system 1400 comprises at least one spinneret 1402 d havingat least two, non-overlapping second channels 1416 configured to extrudethe second polymer 1418, and at least two, non-overlapping threechannels 1422 configured to extrude the third polymer 1424. Suchconfiguration may produce a first type of multicomponent, islands-in-seananofiber such as described, e.g., in FIG. 8.

FIGS. 14I-14J provide a cross-sectional and top-down view of anembodiment in which the system 1400 comprises at least one spinneret1402 e configured to form a second type of multicomponent,islands-in-sea nanofiber (as described, e.g., in FIG. 9). As shown inthe top down view provided in FIG. 14J, the at least one spinneret 1402e may comprise four of the second channels 1416 in spaced relation withone another, and further disposed within an interior portion of thefirst channel 1408, where each of the second channels 1416 areconcentrically disposed around an inner third channel 1422. In someembodiments, the first, second, and third channels 1408, 1416, 1422 maysimultaneously extrude the first, second, and third polymers 1412, 1418,1424, respectively, to form multicomponent, islands-in-sea nanofibers,which may travel, or be drawn, toward the substrate 1404 to form thesingle layer 1406 thereupon.

It is of note that the at least one spinneret 1402 e of FIGS. 14I-14J isnot limited to the number or configuration of the second channels 1416or third channels 1422. Rather, the spinneret 1402 e may include anynumber or configuration of the second channels 1416 and/or thirdchannels 1422 so as to achieve a desired number and configuration of the“islands” comprising the second polymer 1418 and/or the third polymer1424, and which are disposed within the “sea” of the first material1412.

In some embodiments, the second channel 1416 and/or the third channel1422 of spinneret 1402 e may each independently have a cross-sectionalshape that is substantially rounded (e.g., circular, elliptical, etc.).Moreover, the first channel 1408 of spinneret 1402 e may have a crosssectional shape that is substantially rounded (e.g., circular,elliptical, etc.), square, rectangular, irregular, or other suchsuitable shape, in some embodiments. In some embodiments, each of thefirst, second, and third channels 1408, 1416, 1422 of spinneret 1402 emay have a rounded (e.g., circular, elliptical, etc.) cross-sectionalshape.

FIG. 14K provides a cross-sectional view of an embodiment in which thesystem 1400 comprises at least one spinneret 1402 f configured to formbicomponent or multicomponent fully coated, partially coated, dispersed,or aggregate nanofibers (as described, e.g., in FIGS. 10A-10C, 11A-11E,12, 13A-13E). As shown in FIG. 14K, the spinneret 1402 f comprise asingle channel 1408 having a first surface 1410 c in fluid communicationwith solution comprising a mixture of at least two polymers, and asecond surface 1414 c from which the combination of polymers 1426 isextruded. For instance, in some embodiments, the solution, and thereforethe resulting polymers 1426, may comprise a mixture of the first andsecond polymers 1412, 1418. In some embodiments, the solution, andtherefore the resulting polymers 1426, may comprise a mixture of thefirst, second, and third polymers 1412, 1418, 1424. In some embodiments,the solution may be a homogenous mixture of the respective polymers. Insome embodiments, the solution may a non-homogeneous mixture of therespective polymers. During the extrusion process, phase separation ofthe polymers will occur, thereby resulting in nanofibers comprisingirregular arrangements of said polymers (e.g., bicomponent ormulticomponent fully coated nanofibers as shown in FIGS. 3A-3C and FIGS.10A-10C, respectively; bicomponent or multicomponent partially coatednanofibers as shown in FIGS. 4A-4D and FIGS. 11A-11E, respectively;bicomponent or multicomponent dispersed as shown in FIG. 5 and FIG. 12,respectively; or bicomponent or multicomponent aggregate nanofibers asshown in FIGS. 6A-6D and FIGS. 13A-13E, respectively.

In some embodiments, the single channel 1408 a of spinneret 1402 f mayhave a cross sectional shape that is substantially rounded (e.g.,circular, elliptical, etc.), square, rectangular, irregular, or othersuch suitable shape, in some embodiments. In some embodiments, thesingle channel 1408 of spinneret 1402 f may have a cross sectional shapethat is substantially rounded.

In some embodiments, the system 1400 described in any of FIGS. 14A-14Kmay extrude the desired polymers via an electrospinning ofelectrospraying process. Cross-sectional, side views of simplifiedschematics of such an electrospinning or electrospraying process isprovided in FIGS. 15A-15C.

As shown in FIGS. 15A-15C, a power source 1502 may be operativelycoupled to the at least one spinneret 1402 (e.g., spinneret 1402 a, 1402b, 1402 c, 1402 d, 1402 e, or 1402 f) and configured to supply a highvoltage thereto. When a sufficiently high voltage is applied to a liquiddroplet formed near the surface 1504 of the spinneret 1402, the body ofthe liquid becomes charged, and electrostatic repulsion counteracts thesurface tension such that the droplet is stretched, and, at a criticalpoint, a stream of liquid erupts from the surface 1504. In instanceswhere the molecular cohesion of the liquid is sufficiently high, streambreakup does not occur (if stream breakup does occur, droplets areelectrosprayed) and a charged liquid jet is formed. As the jet dries inflight, the mode of current flow changes from ohmic to convective as thecharge migrates to the surface of the fiber. The jet is then elongatedby a whipping process caused by electrostatic repulsion initiated atsmall bends in the fiber, until it is finally deposited on the groundcollector (substrate 1506). The elongation and thinning of the fiberresulting from this bending instability leads to the formation ofuniform fibers with nanometer-scale diameters, in some embodiments.

As also shown in FIGS. 15A-15C, such electrospinning (orelectrospraying) process may be a top-down process in which the at leastone spinneret 1402 (e.g., spinneret 1402 a, 1402 b, 1402 c, 1402 d, 1402e, or 1402 f) is vertically positioned above the substrate 1506 (FIG.15A), and the nanofibers are generated downward; a bottom-up process inwhich the substrate 1506 is vertically positioned above the spinneret1402 (FIG. 15B), and the nanofibers are generated in an upwarddirection; or a vertical process in which the substrate 1506 ishorizontally positioned relative to the spinneret 1402 (FIG. 15C), andthe fibers are generated in horizontal/side-ways direction.

With continued reference to FIGS. 14A-14K, the system 1400 may comprise,in some embodiments, a single spinneret 1402, e.g., a single spinneret1402 a configured to extrude a bicomponent, coaxial nanofibers; a singlespinneret 1402 b configured to extrude bicomponent, islands-in-seananofibers; a single spinneret 1402 c configured to extrudemulticomponent, coaxial nanofibers; a single spinneret 1402 d configuredto extrude a first type of multicomponent, islands-in-sea nanofibers; asingle spinneret 1403 e configure to extrude a second type ofmulticomponent, islands-in-sea nanofiber; or a single spinneret 1402 fconfigured to extrude fully coated, partially coated, dispersed, oraggregate nanofibers. See, e.g., FIG. 16A for an exemplary schematic ofa system comprising a single type of spinneret.

In some embodiments, the system 1400 may comprise a plurality ofspinnerets 1402, where each spinneret 1402 is independently a spinneret1402 a configured to extrude bicomponent, coaxial nanofibers; aspinneret 1402 b configured to extrude bicomponent, islands-in-seananofibers; a spinneret 1402 c configured to extrude multicomponent,coaxial nanofibers; a spinneret 1402 d configured to extrude a firsttype of multicomponent, islands-in-sea nanofibers; a spinneret 1403 econfigure to extrude a second type of multicomponent, islands-in-seananofibers; or a spinneret 1402 f configured to extrude fully coated,partially coated, dispersed, or aggregate nanofibers. In someembodiments, the system 1400 may comprise a plurality of spinnerets,where each spinneret is of the same type (e.g., spinneret 1402 a,spinneret 1402 b, spinneret 1402 c, spinneret 1402 d, spinneret 1402 e,or spinneret 1402 f). In some embodiments, the system 1400 may comprisea plurality of spinnerets 1402, where at least two spinnerets 1402 areof a different type (e.g., spinneret 1402 a, spinneret 1402 b, spinneret1402 c, spinneret 1402 d, spinneret 1402 e, or spinneret 1402 f) fromone another. See, e.g., FIG. 16B for an exemplary schematic of a systemcomprising a plurality of spinnerets.

In other embodiments in which the system 1400 may comprise a pluralityof spinnerets 1402, as described, e.g., in FIG. 16B, at least onespinneret may be configured to extrude a first polymer, e.g., and atleast another spinneret may be configured to extrude a second polymermaterial, where the first and second polymers comprise a differentcomposition, dipole moment, and/or degree of adhesiveness, as oneanother.

In some embodiments, the system 1400 may comprise at least two, at leastthree, at least four, etc. sets/groups 1602 (a, b, c, etc.) ofspinnerets 1402, where each set/group may independently comprise atleast two spinnerets 1402. In some embodiments, at least one of saidsets/groups may comprise a different type of spinneret (e.g., spinneret1402 a, spinneret 1402 b, spinneret 1402 c, spinneret 1402 d, spinneret1402 e, or spinneret 1402 f) as compared to the type of spinnerets of atleast another of said set/groups. In some embodiment, at least two ofsaid sets/groups may comprise the same type of spinneret (e.g.,spinneret 1402 a, spinneret 1402 b, spinneret 1402 c, spinneret 1402 d,spinneret 1402 e, or spinneret 1402 f). See, e.g., FIG. 16C for anexemplary schematic of a system comprising at least four sets/groups ofspinnerets.

In other embodiments in which the system 1400 may comprise a pluralityof spinnerets 1402, as described, e.g., in FIG. 16C, at least one of thesets (e.g., 1602 a) of spinnerets may be configured to extrude a firstpolymer, e.g., and at least another of the sets (e.g., 1602 b) ofspinnerets may be configured to extrude a second polymer material, wherethe first and second polymers comprise a different composition, dipolemoment, and/or degree of adhesiveness, as one another.

In embodiments in which the system 1400 comprises a single spinneret1402 (e.g., as shown in FIG. 16A) or a plurality of spinnerets 1402(e.g., as shown in FIGS. 16B-16C), the system 1400 may comprise ascaffold 1604 that is coupled to, and supports, the spinneret(s) 1402.In some embodiments, the scaffold 1604, and particularly the outerperiphery thereof, may have a shape selected from a rectangle, atriangle, a parallelogram, an echelon, a hexagon, an octagon, a circle,a square, or an irregular shape.

In some embodiments, the scaffold 1602 may comprise a total number ofspinnerets 1402 ranging from about 1 spinneret to about 5000 spinnerets,about 5 to about 2500 spinnerets, about 10 to about 1000 spinnerets, orabout 20 to about 500 spinnerets. In some embodiments, the scaffold 1602may comprise a total number of spinnerets 1402 ranging between andincluding any two of the following values: about 1, about 2, about 4,about 6, about 8, about 10, about 12, about 14, about 16, about 18,about 20, about 40, about 60, about 80, about 100, about 120, about 140,about 160, about 180, about 200, about 220, about 240, about 260, about280, about 300, about 320, about 340, about 360, about 380, about 400,about 420, about 440, about 460, about 480, about 500, about 520, about540, about 560, about 580, about 600, about 620, about 640, about 660,about 680, about 700, about 720, about 740, about 760, about 780, about800, about 820, about 840, about 860, about 880, about 900, about 920,about 940, about 960, about 980, about 1000, about 1050, about 1100,about 1150, about 1200, about 1250, about 1300, about 1350, about 1400,about 1450, about 1500, about 1550, about 1600, about 1650, about 1700,about 1750, about 1800, about 1850, about 1900, about 1950, about 2000,about 2050, about 2100, about 2150, about 2200, about 2250, about 2300,about 2350, about 2400, about 2450, about 2500, about 2550, about 2600,about 2650, about 2700, about 2750, about 2800, about 2850, about 2900,about 2950, about 3000, about 3050, about 3100, about 3150, about 3200,about 3250, about 3300, about 3350, about 3400, about 3450, about 3500,about 3550, about 3600, about 3650, about 3700, about 3750, about 3800,about 385, about 3900, about 3950, about 4000, about 4050, about 4100,about 4150, about 4200, about 4250, about 4300, about 4350, about 4400,about 4450, about 4500, about 4550, about 4600, about 4650, about 4700,about 4750, about 4800, about 4850, about 4900, about 4950, and about5000.

b. Needleless (or Needle-Free) Systems

In some embodiments, the nanofibers disclosed herein may be formed viasystems comprising one or more needle-free (or needleless) spinnerets.FIGS. 17A-17D provide exemplary schematics of a system comprising atleast one needle-free spinneret 1702, according to various embodiments.

As shown in FIGS. 17A-17B, the needle-free spinneret 1702 may comprise asolution dipping component (particle) 1704 in contact with a mixture1706 (i.e., the source of the material to be formed into fiber). In someembodiments, the mixture 1706 may comprise a first solution comprisingat least a first polymer, as disclosed herein, and a second solutioncomprising at least a second polymer, as disclosed herein. In someembodiments in which the mixture 1706 comprises at least a first polymersolution and at least a second polymer solution, the ratio of the firstpolymer solution to the second polymer solution is about 100:1 to about1:100. In some embodiments in which the mixture 1706 comprises at leasta first polymer solution and at least a second polymer solution, theratio of the first polymer solution to the second polymer solution isabout 100:1 to about 1:1, about 75:1 to about 1:1, about 50:1 to about1:1, about 25:1 to about 1:1, about 10:1 to about 1:1, about 5:1 toabout 1:1, or about 1:1. In some embodiments in which the mixture 1706comprises at least a first polymer solution and at least a secondpolymer solution, the ratio of the first polymer solution to the secondpolymer solution is about 1:100 to about 1:1, about 1:75 to about 1:1,about 1:50 to about 1:1, about 1:25 to about 1:1, about 1:10 to about1:1, about 1:5 to about 1:1, or about 1:1. In some embodiments in whichthe mixture 1706 comprises at least a first polymer solution and atleast a second polymer solution, the ratio of the first polymer solutionto the second polymer solution is about 1:1.

In some embodiments, the mixture 1706 may comprise a solution comprisingat least the first polymer, as disclosed herein, a second solutioncomprising the second polymer, as disclosed herein, and a third solutioncomprising a third polymer, as disclosed herein.

In some embodiments, the mixture 1706 may be a homogeneous mixture ofthe respective polymers. In some embodiments, the mixture 1706 may be anon-homogenous mixture of the respective polymers. In some embodiments,phase separation of the polymers in the mixture 1706 may occur duringthe extrusion process from the needle-free spinneret 1702, therebyforming bicomponent or multicomponent nanofibers, where each nanofiberindependently comprises one of the irregular arrangements, or anycombination thereof, of the respective polymers as disclosed herein(e.g., bicomponent or multicomponent fully coated nanofibers as shown inFIGS. 3A-3C and FIGS. 10A-10C, respectively; bicomponent ormulticomponent partially coated nanofibers as shown in FIGS. 4A-4D andFIGS. 11A-11E, respectively; bicomponent or multicomponent dispersed asshown in FIG. 5 and FIG. 12, respectively; or bicomponent ormulticomponent aggregate nanofibers as shown in FIGS. 6A-6D and FIGS.13A-13E, respectively.

For instance, in some embodiments the mixture 1706 may comprise asolution comprising the first and second polymers, as disclosed herein,where phase separation thereof during the extrusion process results in aplurality of bicomponent nanofibers, each of which independentlycomprises a fully coated structure (see, e.g., FIGS. 3A-3C), a partiallycoated structure (see, e.g., FIGS. 4A-4D), a dispersed structure (see,e.g., FIG. 5), an aggregate structure (see, e.g., FIGS. 6A-6D), orcombinations thereof. In some embodiments, one or more of the resultingbicomponent nanofibers may comprise a combination of two or more of theaforementioned structures. One example of such a combination may bewhere at least one of the bicomponent nanofibers has a dispersedstructure (e.g., with the first layer dispersed within/throughout thesecond layer), where one or more portions of said bicomponent, dispersednanofiber also has a partially coated structure (e.g., is also partiallycoated with the first layer).

In some embodiments the mixture 1706 may comprise a solution comprisingthe first, second, and third polymers, as disclosed herein, where phaseseparation thereof during the extrusion process results in a pluralityof multicomponent nanofibers, each of which independently comprises afully coated structure (see, e.g., FIGS. 10A-10C), a partially coatedstructure (see, e.g., FIGS. 11A-11E), a dispersed structure (see, e.g.,FIG. 12), an aggregate structure (see, e.g., FIGS. 13A-13E), orcombinations thereof. In some embodiments, one or more of the resultingmulticomponent nanofibers may comprise a combination of two or more ofthe aforementioned structures. One example of such a combination may bewhere at least one of the multicomponent nanofibers has a dispersedstructure (e.g., with the first layer and second layers dispersedwithin/throughout the third layer), where one or more portions of saidmulticomponent, dispersed nanofiber also has a partially coatedstructure (e.g., is also partially coated with the first and/or secondlayers).

As also shown in FIGS. 17A-17B, the needle-free spinneret 1702 may beoperatively coupled to a power source 1708 configured to supply a highvoltage thereto. In some embodiments, such as shown, e.g., in FIGS.17A-17B, the power source 1708 may be coupled to the solution dippingcomponent 1704. However, in some embodiments, power source 1708 may becoupled to the dipping solution 1706, and particularly the container inwhich said dipping solution 1706 is disposed.

The solution dipping component 1704 may be configured to rotate, suchthat the mixture is loaded onto, and covers, the surface 1710 of thedipping component 1704. The mixture 1706 may form conical spikes on thesurface 1710 of the dipping component 1704 due to rotation thereof. Uponapplication of a sufficiently high voltage, the conical spikes mayconcentrate the electrical charges and further stretch (e.g., formTaylor cones) when the electrostatic repulsion counteracts the surfacetension. Once a critical point is reached, streams of liquid (e.g.,solution jets) may erupt from the surface 1710 of the of the dippingcomponent 1704 to form the bicomponent or multicomponent nanofibers1712, which are collected on the ground collector (e.g., substrate 1714)positioned vertically above the needle-free spinneret 1702.

In some embodiments, the dipping component 1704 may have a spherical,elliptical, or otherwise rounded shape. In some embodiments, the dippingcomponent 1704 may be a rotatable roller or ball.

In some embodiments, the surface 1710 of the dipping component 1704 maybe rough or smooth. FIG. 17A illustrates one embodiment in which thesurface 1710 of the dipping component 1704 is rough, and particularlycomprises a plurality of fabricated spikes. Conversely, FIG. 17Billustrates one embodiment in which the surface 1710 of the dippingcomponent 1704 is substantially smooth.

FIGS. 17C-17D provide additional embodiments of a needle-free spinneret1702, in which the solution dipping component 1704 comprises a thread(or chain) 1714 connecting a plurality of dipping elements (particles)1716. The thread 1714 may be configured to rotate so as to allow thedipping elements 1716 to be coated with the solution 1706. These dippingelements 416 may have a substantially rough exterior surface 1710, asshown in the embodiment of FIG. 17C, or a substantially smooth exteriorsurface 1710, as shown in the embodiment of FIG. 17D.

c. Systems for Producing a Multifunctional Nanofiber Web

Referring now to FIG. 18, a system 1800 for producing multifunctionalnanofiber webs is shown, according to one embodiment. The system 1800,or components/features thereof, in FIG. 18 may be implemented incombination with, or as an alternative to, other systems, orcomponents/features thereof, described herein, such as those describedwith reference to other embodiments and FIGS. The system 1800 mayadditionally be utilized in any of the methods for making and/or usingnanofibers described herein. The system 1800 may also be used in variousapplications and/or in permutations, which may or may not be noted inthe illustrative embodiments described herein. For instance, the system1800 may include more or less features/components than those shown inFIG. 18, in some embodiments. Moreover, the system 1800 is also notlimited to the size, shape, number of components/features, etc.specifically shown in FIG. 18.

As shown in FIG. 18, the system 1800 may include one or more polymerforming (e.g., electrospinning or electrospraying) stations 1802 (a, b,c, etc.). In some embodiments, at least one of the stations 1802 may beconfigured to produce a nanofiber web comprising the bicomponent ormulticomponent nanofibers disclosed herein. For instance, at least oneof the stations 1802 may include system 1400 as described in any one ofFIGS. 14A-14J.

In addition to one or more stations 1802 configured to produce thenanofiber web comprising bicomponent or multicomponent nanofibers, asdisclosed herein, the system 1800 may optionally comprise at least onestation 1802 configured to extrude, e.g., via an electrospraying orelectrospinning process, one or more additional materials (e.g., polymermaterial(s)) independently selected to provide a desired functionalperformance. Such functional performance may include, but is not limitedto, light emission, heat insulation, heat resistance, sterilization,flame resistance, degradation, self-cleaning, anti-corrosion, adhesion,combinations thereof, etc. For instance, in one embodiment, the systemmay comprise at least one station (e.g., 1802 a) configured to producebicomponent or multicomponent nanofibers, as disclosed herein, and atleast one station (e.g., 1802 b) configured to extrude one or moreadditional materials independently selected to provide a desiredfunctional performance.

In some embodiments, the system 1800 may optionally include one or morespray additive stations 1804 (a, b, etc.) and/or one or more rolleradditive stations 1806 (a, b, etc.) to provide a desired, functional endproduct.

In some embodiments, the substrate may be introduced prior to or afterthe process described in FIG. 18, or between any of the steps describedtherein.

3. Methods

Referring now to FIG. 19, a flowchart of a method 1900 of preparing abicomponent or multicomponent nanofiber with an electrospinning deviceis shown according to one embodiment. The method 1900 may be implementedin conjunction with any of the features/components described herein,such as those described with reference to other embodiments and FIGS.The method 1900 may also be used for various applications and/oraccording to various permutations, which may or may not be noted in theillustrative embodiments/aspects described herein. For instance, themethod 1900 may include more or less operations/steps than those shownin FIG. 19, in some embodiments. Moreover, the method 1900 is notlimited by the order of operations/steps shown therein.

As shown in FIG. 19, the method 1900 comprises supplying a solution of afirst polymer to a first channel of a spinneret of an electrospinningdevice, and supplying a solution of a second polymer to the secondchannel of the spinneret. See Steps 1902 and 1904, respectively. Themethod 1900 further comprises electrospinning the solutions, through therespective channels, onto the surface of a substrate, thereby preparinga fibrous structure comprising fibers having a first layer comprisingthe first polymer and a second layer inside the first layer andcomprising the second polymer. See Step 1906.

In some embodiments of FIG. 19, one of the polymers may have a dipolemoment greater than about 2 debye (D) and another polymer may have adipole moment lower than about 1 D. In some embodiments, the firstpolymer may have a dipole moment greater than about 2 D and the secondpolymer may have a dipole moment lower than about 1 D.

In some embodiments, the first channel and the second channel of theelectrospinning device may be coaxial (see, e.g. system 1400 of FIGS.14A-14B configured to prepare bicomponent, coaxial nanofibers).

In some embodiments of FIG. 19, the spinneret may further comprise athird channel inside the second channel, and therefore the preparedfibers may comprise a first layer, a second layer inside the firstlayer, and a third layer inside the second layer (see e.g. system 1400of FIGS. 14E-14F configured to prepare multicomponent, coaxialnanofibers). In such embodiments, the first layer may a dipole momentgreater than about 2 D, the second polymer may have a dipole momentlower than about 1 D, and the third layer may have a dipole moment equalto or greater than about 1 D. In some embodiments. the first layer andthe third layer comprise the same polymer. In some embodiments, thefirst layer and the third layer comprise different polymers.

In some embodiments of FIG. 19, the spinneret may comprise a pluralityof non-overlapping second channels inside the first channel, andtherefore the prepared fibers comprise a first layer and a plurality ofnon-overlapping second layers inside the first layer (see, e.g., system1400 of FIGS. 14C-14D configured to prepare bicomponent, islands-in-seananofibers). In such embodiments, the first layer may a dipole momentgreater than about 2 D, and at least one of the second layers may have adipole moment lower than about 1 D. In some embodiments, the secondlayers may each comprise the same polymer having a dipole moment lowerthan about 1 D. In some embodiments, at least two of the second layersmay comprise different polymers from one another provided that saidpolymers have a dipole moment lower than about 1 D.

In some embodiments of FIG. 19, the spinneret may comprise a pluralityof non-overlapping second channels and a plurality of non-overlappingthird channels inside the first channel, and therefore the preparedfibers comprise a first layer and a plurality of non-overlapping secondlayers and non-overlapping third layers inside the first layer (see,e.g., system 1400 of FIGS. 14G-14H configured to prepare a first type ofmulticomponent, islands-in-sea nanofibers). In such embodiments, thefirst layer may a dipole moment greater than about 2 D, the secondlayers may have a dipole moment lower than about 1 D, and the thirdlayers may have a dipole moment equal to or greater than about 1 D.

In some embodiments of FIG. 19, the spinneret may comprise a pluralityof non-overlapping second channels inside the first channel, and a thirdchannel inside each of the plurality of second channels (see, e.g.,system 1400 of FIGS. 14G-14H configured to prepare a second type ofmulticomponent, islands-in-sea nanofibers).

Referring now to FIG. 20, a flowchart of a method 2000 of preparing abicomponent or multicomponent nanofiber is shown according to anotherembodiment. The method 2000 may be implemented in conjunction with anyof the features/components described herein, such as those describedwith reference to other embodiments and FIGS. The method 2000 may alsobe used for various applications and/or according to variouspermutations, which may or may not be noted in the illustrativeembodiments/aspects described herein. For instance, the method 2000 mayinclude more or less operations/steps than those shown in FIG. 20, insome embodiments. Moreover, the method 2000 is not limited by the orderof operations/steps shown therein.

As shown in FIG. 20, the method 2000 comprises admixing a first polymersolution with a second polymer solution under suitable conditions toprepare a mixture. See Step 2002. In some embodiments, the mixture maycomprise about equal volumes of the first polymer solution and thesecond polymer solution. In some embodiments, the ratio of the firstpolymer solution to the second polymer solution in the mixture is about1:100 to about 100:1. In some embodiments, the ratio of the firstpolymer solution to the second polymer solution in the mixture is about100:1 to about 1:1, about 75:1 to about 1:1, about 50:1 to about 1:1,about 25:1 to about 1:1, about 10:1 to about 1:1, about 5:1 to about1:1, or about 1:1. In some embodiments, the ratio of the first polymersolution to the second polymer solution in the mixture is about 1:100 toabout 1:1, about 1:75 to about 1:1, about 1:50 to about 1:1, about 1:25to about 1:1, about 1:10 to about 1:1, about 1:5 to about 1:1, or about1:1. In some embodiments, the ratio of the first polymer solution to thesecond polymer solution in the mixture is about 1:1.

In some embodiments of FIG. 20, at least a portion of the mixture ishomogeneous. In some embodiments, substantially all of the mixture ishomogeneous. For instance, in some embodiments, the first polymersolution may be substantially evenly dispersed in the second polymersolution. In some embodiments, the second polymer solution may besubstantially evenly dispersed in the first polymer solution. Asdiscussed below, phase separation of the mixture may occur during thesubsequent electrospinning process.

In some embodiments of FIG. 20, at least a portion of the mixture isnon-homogeneous. In some embodiments, substantially all of the mixtureis non-homogeneous. As discussed below, phase separation of the mixturemay be maintained and/or further increased during the subsequentelectrospinning process

As also shown in FIG. 20, the method 2000 additionally compriseselectrospinning the mixture onto the surface of a substrate underconditions to allow the first polymer solution and the second polymersolution to maintain or separate into different phases, therebypreparing a fibrous structure comprising fibers having the first polymerand the second polymer in separate portions. See Step 2004.

In some embodiments, the first polymer and the second polymer havedifferent dipole moments In some embodiments of FIG. 20, the firstpolymer has a dipole moment greater than about 2 D and the secondpolymer has a dipole moment lower than about 1 D.

In some embodiments of FIG. 20, the first polymer solution comprises afirst therapeutic molecule. In some embodiments, the second polymersolution comprises a second therapeutic molecule. In some embodiments,the first therapeutic molecule requires a shorter release time in humanpatients than the second therapeutic molecule. In some embodiments, thesecond therapeutic molecule requires a shorter release time in humanpatients than the first therapeutic molecule.

Referring now to FIG. 21, a flowchart of a method 2100 of preparing afibrous structure with an electrospinning device comprising a pluralityof spinnerets is shown according to one embodiment. The method 2100 maybe implemented in conjunction with any of the features/componentsdescribed herein, such as those described with reference to otherembodiments and FIGS. The method 2100 may also be used for variousapplications and/or according to various permutations, which may or maynot be noted in the illustrative embodiments/aspects described herein.For instance, the method 2100 may include more or less operations/stepsthan those shown in FIG. 21, in some embodiments. Moreover, the method2100 is not limited by the order of operations/steps shown therein.

As shown in FIG. 21, the method 2100 comprises supplying a solution of afirst polymer to at least one of the spinnerets, and supplying asolution of a second polymer to at least another of the spinnerets. SeeSteps 2102 and 2104, respectively. The method 2100 additionallycomprises electrospinning the solutions, through the respectivespinnerets, onto the surface of a substrate, thereby preparing a fibrousstructure comprising fibers having different polymers. See step 2106.

In some embodiments, the electrospinning device may comprise at least arow of spinnerets and at least one of the spinnerets in the row isconnected to the first solution and at least another of the spinneretsin the row is connected to the second solution (see, e.g., the spinneretconfigurations shown in FIGS. 16B-16C). In some embodiments, theelectrospinning device comprise a plurality of rows of spinnerets andall spinnerets in at least one row are connected to the first solutionand all spinnerets in at least another row are connected to the secondsolution.

In some embodiments of FIG. 21, the first polymer and the second polymerhave different dipole moments. In some embodiments, one of the polymershas a dipole moment greater than about 2 D and another polymer has adipole moment lower than about 1 D.

Referring now to FIG. 22, a flowchart of a method 2200 of preparing abicomponent or multicomponent nanofiber is shown according to oneembodiment. The method 2200 may be implemented in conjunction with anyof the features/components described herein, such as those describedwith reference to other embodiments and FIGS. The method 2200 may alsobe used for various applications and/or according to variouspermutations, which may or may not be noted in the illustrativeembodiments/aspects described herein. For instance, the method 2200 mayinclude more or less operations/steps than those shown in FIG. 22, insome embodiments. Moreover, the method 2200 is not limited by the orderof operations/steps shown therein.

As shown in FIG. 22, the method comprises dipping a particle in amixture of a first polymer solution and a second polymer solution, andlifting the particle out of the mixture under conditions to allow theparticle to be covered with the mixture. See Steps 2202 and 2204,respectively. The method 2200 further comprises applying an electricalfield between the particle and a collector to force a nanofiber to formfrom the mixture on the particle and be collected on the collector,wherein the nanofiber comprises both the first polymer and the secondpolymer. See Step 2206.

In some embodiments of FIG. 22, at least part of the first solution hasphase separation from the second solution. In some embodiments, at leastpart of the first polymer solution is substantially located at thesurface of the mixture.

In some embodiments of FIG. 22, the particle may have an exterior roughsurface (see, e.g., the needleless system described in FIG. 17A). Insome embodiments, the particle may have a smooth exterior surface (see,e.g., the needleless system described in FIG. 17A).

In some embodiments of FIG. 22, the particle may be connected to one ormore particles through a thread (see, e.g., the needleless systemdescribed in FIG. 17C-17D).

Referring now to FIG. 23, a flowchart of a method 2300 of preparing amultifunctional web is shown according to one embodiment. The method2300 may be implemented in conjunction with any of thefeatures/components described herein, such as those described withreference to other embodiments and FIGS. The method 2300 may also beused for various applications and/or according to various permutations,which may or may not be noted in the illustrative embodiments/aspectsdescribed herein. For instance, the method 2300 may include more or lessoperations/steps than those shown in FIG. 23, in some embodiments.Moreover, the method 2300 is not limited by the order ofoperations/steps shown therein.

As shown in FIG. 23, the method 2300 comprises forming a first layer ofa nanofiber web on a substrate by a first electrospinning system, andadding a functional layer on the nanofiber on the first layer with asecond electrospinning system, a spray system, or a rolling system. SeeSteps 2302 and 2304, respectively. In some embodiments the first layerand the second layer comprise different polymers or have differentdipole moments.

In some embodiments of FIG. 23, one of the polymers has a dipole momentgreater than about 2 D and another of the polymers has a dipole momentlower than about 1 D.

In some embodiments of FIG. 23, the method 2300 further comprises addingone or more additives by electrospinning, electrospraying or rollerelectrospinning.

In some embodiments, the resulting multicomponent nanofiber web isconfigured to be useful for light emission, heat insulation, heatresistance, sterilization, flame resistance, degradation, self-cleaning,anti-corrosion, or combinations thereof.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs.

Throughout the present specification and claims, unless the contextrequires otherwise, the word “comprise” and variations thereof (e.g.,“comprises” and “comprising”) are to be construed in an open, inclusivesense, that is as “including, but not limited to.” Additionally, thesingular forms “a,” “an” and “the” include plural referents unless thecontext clearly dictates otherwise.

Recitation of numeric ranges of values throughout the specification isintended to serve as a shorthand notation of referring individually toeach separate value falling within the range inclusive of the valuesdefining the range, and each separate value is incorporated in thespecification as it were individually recited herein.

Reference to “about” a value or parameter herein includes (anddescribes) embodiments that are directed to that value or parameter perse. In some embodiments, the term “about” includes the indicated amount±10%.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment of the present invention. Thus, the appearances of thephrases “in one embodiment” or “in an embodiment” in various placesthroughout this specification are not necessarily all referring to thesame embodiment, but may be in some instances. Furthermore, theparticular features, structures, or characteristics may be combined inany suitable manner in one or more embodiments.

In addition, where features or aspects of the invention are described interms of Markush groups, those skilled in the art will recognize thatthe invention is also thereby described in terms of any individualmember or subgroup of members of the Markush group.

All publications, patent applications, patents, and other referencesmentioned herein are expressly incorporated by reference in theirentirety, to the same extent as if each were incorporated by referenceindividually. In case of conflict, the present specification, includingdefinitions, will control.

The invention described and claimed herein is not to be limited in scopeby the specific embodiments disclosed herein, as these embodiments areintended as illustrations of several aspects of the invention. Indeed,various modifications of the invention in addition to those shown anddescribed herein will become apparent to those skilled in the art fromthe foregoing description. Such modifications include the substitutionof known equivalents for any aspect of the invention in order to achievethe same result in substantially the same way. Such modifications arealso intended to fall within the scope of the appended claims.

What is claimed is:
 1. A method of preparing a bicomponent ormulticomponent nanofiber with an electrospinning device comprising aspinneret comprising a first channel and a second channel inside thefirst channel, the method comprising: supplying a solution of a firstpolymer to a first channel; supplying a solution of a second polymer tothe second channel; and electrospinning the solutions, through therespective channels, onto the surface of a substrate, thereby preparinga fibrous structure comprising fibers having a first layer comprisingthe first polymer and a second layer inside the first layer andcomprising the second polymer, wherein the first polymer and the secondpolymer have different dipole moments.
 2. The method of claim 1, whereinone of the polymers has a dipole moment greater than about 2 debye (D)and another polymer has a dipole moment lower than about 1 D.
 3. Themethod of claim 1, wherein spinneret further comprises a third channelinside the second channel, and therefore the prepared fibers comprise afirst layer, a second layer inside the first layer, and a third layerinside the second layer.
 4. The method of claim 3, wherein the firstlayer has a dipole moment greater than about 2 D, the second polymer hasa dipole moment lower than about 1 D, and the third layer has a dipolemoment greater than about 2 D.
 5. The method of claim 1, wherein thespinneret comprises a plurality of non-overlapping second channelsinside the first channel, and therefore the prepared fibers comprise afirst layer and a plurality of non-overlapping second layers inside thefirst layer.
 6. The method of claim 5, wherein at least one of thesecond layers has a dipole moment lower than about 1 D.
 7. The method ofclaim 5, wherein the spinneret further comprises a third channel insideeach of the plurality of second channels.
 8. A method of preparing abicomponent or multicomponent nanofiber, the method comprising: admixinga first polymer solution with a second polymer solution under suitableconditions to prepare a mixture; and electrospinning the mixture ontothe surface of a substrate under conditions to allow the first polymersolution and the second polymer solution to maintain or separate intodifferent phases, thereby preparing a fibrous structure comprisingfibers having the first polymer and the second polymer in separateportions, wherein the first polymer and the second polymer havedifferent dipole moments.
 9. The method of claim 8, wherein mixturecomprises about equal volumes of the first polymer solution and thesecond polymer solution.
 10. The method of claim 8, wherein, in themixture, the ratio of the first polymer solution to the second polymersolution is about 1:100 to about 100:1, about 1:10 to about 10:1, orabout 1:1.
 11. The method of claim 8, wherein at least part of the firstpolymer solution is phase separated from the second polymer solution.12. A method of preparing a fibrous structure with an electrospinningdevice comprising a plurality of spinnerets, comprising: supplying asolution of a first polymer to at least one of the spinnerets; supplyinga solution of a second polymer to at least another of the spinnerets;and electrospinning the solutions, through the respective spinnerets,onto the surface of a substrate, thereby preparing a fibrous structurecomprising fibers having different polymers, wherein the first polymerand the second polymer have different dipole moments.
 13. The method ofclaim 12, wherein the electrospinning device comprises at least a row ofspinnerets, wherein at least one of the spinnerets in the row isconnected to the first solution and at least another of the spinneretsin the row is connected to the second solution.
 14. The method of claim12, wherein the electrospinning device comprises a plurality of rows ofspinnerets, wherein all spinnerets in at least one row are connected tothe first solution and all spinnerets in at least another row areconnected to the second solution.
 15. The method of claim 12, whereinone of the polymers has a dipole moment greater than about 2 D andanother polymer has a dipole moment lower than about 1 D.
 16. A methodof preparing a bicomponent or multicomponent nanofiber, the methodcomprising: dipping a particle in a mixture of a first polymer solutionand a second polymer solution; lifting the particle out of the mixtureunder conditions to allow the particle to be covered with the mixture;and applying an electrical field between the particle and a collector toforce a nanofiber to form from the mixture on the particle and becollected on the collector, wherein the nanofiber comprises both thefirst polymer and the second polymer.
 17. The method of claim 16,wherein at least part of the first solution has phase separation fromthe second solution.
 18. The method of claim 17, wherein at least partof the first polymer solution is substantially located at the surface ofthe mixture.
 19. The method of claim 16, wherein the particle has anexterior rough surface.
 20. The method of claim 16, wherein the particlehas a smooth exterior surface.
 21. The method of claim 16, wherein theparticle is connected to one or more particles through a thread.
 22. Amethod of preparing a bicomponent or multifunctional nanofiber web,comprising: forming a first layer of a nanofiber web on a substrate byelectrospinning system; and adding a functional layer on the first layerwith a second electrospinning system, spray system, or rolling system,wherein the first layer comprises at least two polymers having differentdipole moments.
 23. The method of claim 22, wherein the multicomponentnanofiber web is configured to be useful for light emission, heatinsulation, heat resistance, sterilization, flame resistance,degradation, self-cleaning, anti-corrosion, or combinations thereof.